[data-structures: expand (P1)](https://github.com/john-cd/rust_howto/issues/280)

Hashset BinaryHeap LinkedList Stack Queue BTreeMap BTreeSet

Alongside arrayvec and tinyvec, heapless has stack-allocated arrays, but also includes:

Arc – like std::sync::Arc but backed by a lock-free memory pool rather than #[global_allocator] Box – like std::boxed::Box but backed by a lock-free memory pool rather than #[global_allocator] BinaryHeap – priority queue IndexMap – hash table IndexSet – hash set LinearMap Object – objects managed by an object pool String Vec mpmc::Q* – multiple producer multiple consumer lock-free queue spsc::Queue – single producer single consumer lock-free queue